1. Field of the Invention
The present invention relates to an artificial respiration apparatus and in particular, to an artificial respiration apparatus of high-frequency oscillation type.
The conventional high-frequency oscillation type respiration apparatus includes three pipe routes 605, 604 and 623 which are connected to a three-way branched pipe 170 having: a patient side opening 171, oxygen supply opening 172, and a discharge opening 173. The patient opening 171 is connected to a patient. The oxygen supply opening 172 is connected to an oxygen supply port. The discharge opening 173 is connected to a discharge exit 607.
2. Description of the Related Art
FIG. 22 schematically shows a discharge route of a conventional respiration apparatus of high-frequency oscillation.
The conventional high-frequency oscillation type respiration apparatus includes three pipe routes 605, 604, and 623 which are connected to a three-way branched pipe 170 having: a patient side opening 171, oxygen supply opening 172, and a discharge opening 173. The patient opening 171 is connected to a patient. The oxygen supply opening 172 is connected to an oxygen supply port. The discharge opening 173 is connected to a discharge exit 807.
With the aforementioned configuration, oxygen is supplied from the oxygen supply port to the oxygen supply opening 172 in a state urged by oscillating pressure. The oxygen is supplied through the oxygen supply opening 172 to the patient side opening 171, reaching lungs of a patient P. On the other hand, carbon dioxide (CO2) discharged from the lungs of the patient P passes through the patient side opening 171, the discharge valve 607 into the atmosphere.
Here, as shown in FIG. 23, the discharge exit 607 has: a casing 607a for introducing a discharge pipe 604 connected to the discharge opening 173; and a discharge port 607b for discharging the carbon dioxide.
However, in the aforementioned conventional apparatus, a negative pressure urging is also carried out so as to discharge carbon dioxide from the lungs of the patient P. Here, the exhaled gas from the patient P is urged into the three-way branched pipe 170. Simultaneously with this, atmospheric air intrudes from the discharge port 607b of the discharge exit as shown in FIG. 24. This results in reduction of the discharged respiration gas from the patient, i.e., reduction of the gas exchange at one cycle of the oscillating air pressure.
Moreover, in this high-frequency gas exchange, it is difficult, to control pressure inside the pipe route 604 so as to maintain an average in-pipe pressure (almost atmospheric pressure) lower than the conventional intermittent forced ventilation. Simultaneously with this, if an exhaled gas quantity is increased, the lowest value of the average in-pipe pressure is increased.
Moreover, in the conventional high-frequency oscillation type artificial respiration method, the in-pipe pressure between the patient and the discharge end has been maintained lower than the conventional intermittent type artificial respiration apparatus. However, when the average in-pipe pressure is set low such as almost atmospheric pressure, the atmospheric air intrudes from the discharge end, and it is difficult to obtain a target pressure. Simultaneously with this, if an exhaled gas amount is increased the average in-pipe pressure is increased.
It is therefore an object of the present invention to provide an artificial respiration apparatus capable of preventing intrusion of the atmospheric air from the discharge end so as to perform gas exchange more effectively.